DESCRIPTION

Bison is a parser generator in the style of
yacc(1).
It should be upwardly compatible with input files designed
for
yacc.

Input files should follow the
yacc convention of ending in
.y. Unlike
yacc, the generated files do not have fixed names, but instead use the prefix
of the input file.
Moreover, if you need to put
C++ code in the input file, you can end his name by a C++-like extension
(.ypp or .y++), then bison will follow your extension to name the
output file (.cpp or .c++).
For instance, a grammar description file named
parse.yxx would produce the generated parser in a file named
parse.tab.cxx, instead of
yaccs y.tab.c or old
Bison versions
parse.tab.c.

This description of the options that can be given to
bison is adapted from the node
Invocation in the
bison.texinfo manual, which should be taken as authoritative.

Bison supports both traditional single-letter options and mnemonic long
option names. Long option names are indicated with
-- instead of
-. Abbreviations for option names are allowed as long as they
are unique. When a long option takes an argument, like
--file-prefix, connect the option name and the argument with
=.

OPTIONS

Tag

Description

-b file-prefix

--file-prefix=file-prefix

Specify a prefix to use for all
bison output file names. The names are
chosen as if the input file were named
file-prefix.c.

-d

Write an extra output file containing macro definitions for the token
type names defined in the grammar and the semantic value type
YYSTYPE, as well as a few
extern variable declarations.

If the parser output file is named
name.c then this file
is named
name.h.

This output file is essential if you wish to put the definition of
yylex in a separate source file, because
yylex needs to be able to refer to token type codes and the variable
yylval.

--defines=defines-file

The behavior of
--defines is the same than
-d option.
The only difference is that it has an optional argument which is
the name of the output filename.

-g

Output a VCG definition of the LALR(1) grammar automaton computed by
Bison. If the grammar file is
foo.y , the VCG output file will be
foo.vcg.

--graph=graph-file

The behavior of
--graph is the same than
-g option. The only difference is that it has an optional argument which
is the name of the output graph filename.

-k

--token-table

This switch causes the
name.tab.c output to include a list of
token names in order by their token numbers; this is defined in the array
yytname. Also generated
are #defines for
YYNTOKENS, YYNNTS, YYNRULES, and
YYNSTATES.

-l

--no-lines

Dont put any
#line preprocessor commands in the parser file.
Ordinarily
bison puts them in the parser file so that the C compiler
and debuggers will associate errors with your source file, the
grammar file. This option causes them to associate errors with the
parser file, treating it an independent source file in its own right.

-n

--no-parser

Do not generate the parser code into the output; generate only
declarations. The generated
name.tab.c file will have only
constant declarations. In addition, a
name.act file is
generated containing a switch statement body containing all the
translated actions.

-o outfile

--output-file=outfile

Specify the name
outfile for the parser file.

The other output files names are constructed from
outfile as described under the
-v and
-d switches.

-p prefix

--name-prefix=prefix

Rename the external symbols used in the parser so that they start with
prefix instead of
yy. The precise list of symbols renamed is
yyparse, yylex, yyerror, yylval, yychar, and
yydebug.

For example, if you use
-p c, the names become
cparse, clex, and so on.

-t

--debug

In the parser file, define the macro
YYDEBUG to 1 if it is not already defined,
so that the debugging facilities are compiled.

-v

--verbose

Write an extra output file containing verbose descriptions of the
parser states and what is done for each type of look-ahead token in
that state.

This file also describes all the conflicts, both those resolved by
operator precedence and the unresolved ones.

The files name is made by removing
.tab.c or
.c from the parser output file name, and adding
.output instead.

Therefore, if the input file is
foo.y, then the parser file is called
foo.tab.c by default. As a consequence, the verbose
output file is called
foo.output.

-V

--version

Print the version number of
bison and exit.

-h

--help

Print a summary of the options to
bison and exit.

-y

--yacc

--fixed-output-files

Equivalent to
-o y.tab.c; the parser output file is called
y.tab.c, and the other outputs are called
y.output and
y.tab.h. The purpose of this switch is to imitate
yaccs output file name conventions.
Thus, the following shell script can substitute for
yacc and is often installed as
yacc:

bison -y "$@"

SEE ALSO

The
Bison Reference Manual, included as the file
bison.texinfo in the
bison source distribution.